drivers/tty/serial/stm32-usart.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Copyright (C) Maxime Coquelin 2015
   4  * Copyright (C) STMicroelectronics SA 2017
   5  * Authors:  Maxime Coquelin <mcoquelin.stm32@gmail.com>
   6  *           Gerald Baeza <gerald.baeza@foss.st.com>
   7  *           Erwan Le Ray <erwan.leray@foss.st.com>
   8  *
   9  * Inspired by st-asc.c from STMicroelectronics (c)
  10  */
  11
  12 #include <linux/clk.h>
  13 #include <linux/console.h>
  14 #include <linux/delay.h>
  15 #include <linux/dma-direction.h>
  16 #include <linux/dmaengine.h>
  17 #include <linux/dma-mapping.h>
  18 #include <linux/io.h>
  19 #include <linux/iopoll.h>
  20 #include <linux/irq.h>
  21 #include <linux/module.h>
  22 #include <linux/of.h>
  23 #include <linux/of_platform.h>
  24 #include <linux/pinctrl/consumer.h>
  25 #include <linux/platform_device.h>
  26 #include <linux/pm_runtime.h>
  27 #include <linux/pm_wakeirq.h>
  28 #include <linux/serial_core.h>
  29 #include <linux/serial.h>
  30 #include <linux/spinlock.h>
  31 #include <linux/sysrq.h>
  32 #include <linux/tty_flip.h>
  33 #include <linux/tty.h>
  34
  35 #include "serial_mctrl_gpio.h"
  36 #include "stm32-usart.h"
  37
  38 static void stm32_usart_stop_tx(struct uart_port *port);
  39 static void stm32_usart_transmit_chars(struct uart_port *port);
  40
  41 static inline struct stm32_port *to_stm32_port(struct uart_port *port)
  42 {
  43         return container_of(port, struct stm32_port, port);
  44 }
  45
  46 static void stm32_usart_set_bits(struct uart_port *port, u32 reg, u32 bits)
  47 {
  48         u32 val;
  49
  50         val = readl_relaxed(port->membase + reg);
  51         val |= bits;
  52         writel_relaxed(val, port->membase + reg);
  53 }
  54
  55 static void stm32_usart_clr_bits(struct uart_port *port, u32 reg, u32 bits)
  56 {
  57         u32 val;
  58
  59         val = readl_relaxed(port->membase + reg);
  60         val &= ~bits;
  61         writel_relaxed(val, port->membase + reg);
  62 }
  63
  64 static void stm32_usart_config_reg_rs485(u32 *cr1, u32 *cr3, u32 delay_ADE,
  65                                          u32 delay_DDE, u32 baud)
  66 {
  67         u32 rs485_deat_dedt;
  68         u32 rs485_deat_dedt_max = (USART_CR1_DEAT_MASK >> USART_CR1_DEAT_SHIFT);
  69         bool over8;
  70
  71         *cr3 |= USART_CR3_DEM;
  72         over8 = *cr1 & USART_CR1_OVER8;
  73
  74         if (over8)
  75                 rs485_deat_dedt = delay_ADE * baud * 8;
  76         else
  77                 rs485_deat_dedt = delay_ADE * baud * 16;
  78
  79         rs485_deat_dedt = DIV_ROUND_CLOSEST(rs485_deat_dedt, 1000);
  80         rs485_deat_dedt = rs485_deat_dedt > rs485_deat_dedt_max ?
  81                           rs485_deat_dedt_max : rs485_deat_dedt;
  82         rs485_deat_dedt = (rs485_deat_dedt << USART_CR1_DEAT_SHIFT) &
  83                            USART_CR1_DEAT_MASK;
  84         *cr1 |= rs485_deat_dedt;
  85
  86         if (over8)
  87                 rs485_deat_dedt = delay_DDE * baud * 8;
  88         else
  89                 rs485_deat_dedt = delay_DDE * baud * 16;
  90
  91         rs485_deat_dedt = DIV_ROUND_CLOSEST(rs485_deat_dedt, 1000);
  92         rs485_deat_dedt = rs485_deat_dedt > rs485_deat_dedt_max ?
  93                           rs485_deat_dedt_max : rs485_deat_dedt;
  94         rs485_deat_dedt = (rs485_deat_dedt << USART_CR1_DEDT_SHIFT) &
  95                            USART_CR1_DEDT_MASK;
  96         *cr1 |= rs485_deat_dedt;
  97 }
  98
  99 static int stm32_usart_config_rs485(struct uart_port *port,
 100                                     struct serial_rs485 *rs485conf)
 101 {
 102         struct stm32_port *stm32_port = to_stm32_port(port);
 103         const struct stm32_usart_offsets *ofs = &stm32_port->info->ofs;
 104         const struct stm32_usart_config *cfg = &stm32_port->info->cfg;
 105         u32 usartdiv, baud, cr1, cr3;
 106         bool over8;
 107
 108         stm32_usart_clr_bits(port, ofs->cr1, BIT(cfg->uart_enable_bit));
 109
 110         port->rs485 = *rs485conf;
 111
 112         rs485conf->flags |= SER_RS485_RX_DURING_TX;
 113
 114         if (rs485conf->flags & SER_RS485_ENABLED) {
 115                 cr1 = readl_relaxed(port->membase + ofs->cr1);
 116                 cr3 = readl_relaxed(port->membase + ofs->cr3);
 117                 usartdiv = readl_relaxed(port->membase + ofs->brr);
 118                 usartdiv = usartdiv & GENMASK(15, 0);
 119                 over8 = cr1 & USART_CR1_OVER8;
 120
 121                 if (over8)
 122                         usartdiv = usartdiv | (usartdiv & GENMASK(4, 0))
 123                                    << USART_BRR_04_R_SHIFT;
 124
 125                 baud = DIV_ROUND_CLOSEST(port->uartclk, usartdiv);
 126                 stm32_usart_config_reg_rs485(&cr1, &cr3,
 127                                              rs485conf->delay_rts_before_send,
 128                                              rs485conf->delay_rts_after_send,
 129                                              baud);
 130
 131                 if (rs485conf->flags & SER_RS485_RTS_ON_SEND) {
 132                         cr3 &= ~USART_CR3_DEP;
 133                         rs485conf->flags &= ~SER_RS485_RTS_AFTER_SEND;
 134                 } else {
 135                         cr3 |= USART_CR3_DEP;
 136                         rs485conf->flags |= SER_RS485_RTS_AFTER_SEND;
 137                 }
 138
 139                 writel_relaxed(cr3, port->membase + ofs->cr3);
 140                 writel_relaxed(cr1, port->membase + ofs->cr1);
 141         } else {
 142                 stm32_usart_clr_bits(port, ofs->cr3,
 143                                      USART_CR3_DEM | USART_CR3_DEP);
 144                 stm32_usart_clr_bits(port, ofs->cr1,
 145                                      USART_CR1_DEDT_MASK | USART_CR1_DEAT_MASK);
 146         }
 147
 148         stm32_usart_set_bits(port, ofs->cr1, BIT(cfg->uart_enable_bit));
 149
 150         return 0;
 151 }
 152
 153 static int stm32_usart_init_rs485(struct uart_port *port,
 154                                   struct platform_device *pdev)
 155 {
 156         struct serial_rs485 *rs485conf = &port->rs485;
 157
 158         rs485conf->flags = 0;
 159         rs485conf->delay_rts_before_send = 0;
 160         rs485conf->delay_rts_after_send = 0;
 161
 162         if (!pdev->dev.of_node)
 163                 return -ENODEV;
 164
 165         return uart_get_rs485_mode(port);
 166 }
 167
 168 static int stm32_usart_pending_rx(struct uart_port *port, u32 *sr,
 169                                   int *last_res, bool threaded)
 170 {
 171         struct stm32_port *stm32_port = to_stm32_port(port);
 172         const struct stm32_usart_offsets *ofs = &stm32_port->info->ofs;
 173         enum dma_status status;
 174         struct dma_tx_state state;
 175
 176         *sr = readl_relaxed(port->membase + ofs->isr);
 177
 178         if (threaded && stm32_port->rx_ch) {
 179                 status = dmaengine_tx_status(stm32_port->rx_ch,
 180                                              stm32_port->rx_ch->cookie,
 181                                              &state);
 182                 if (status == DMA_IN_PROGRESS && (*last_res != state.residue))
 183                         return 1;
 184                 else
 185                         return 0;
 186         } else if (*sr & USART_SR_RXNE) {
 187                 return 1;
 188         }
 189         return 0;
 190 }
 191
 192 static unsigned long stm32_usart_get_char(struct uart_port *port, u32 *sr,
 193                                           int *last_res)
 194 {
 195         struct stm32_port *stm32_port = to_stm32_port(port);
 196         const struct stm32_usart_offsets *ofs = &stm32_port->info->ofs;
 197         unsigned long c;
 198
 199         if (stm32_port->rx_ch) {
 200                 c = stm32_port->rx_buf[RX_BUF_L - (*last_res)--];
 201                 if ((*last_res) == 0)
 202                         *last_res = RX_BUF_L;
 203         } else {
 204                 c = readl_relaxed(port->membase + ofs->rdr);
 205                 /* apply RDR data mask */
 206                 c &= stm32_port->rdr_mask;
 207         }
 208
 209         return c;
 210 }
 211
 212 static void stm32_usart_receive_chars(struct uart_port *port, bool threaded)
 213 {
 214         struct tty_port *tport = &port->state->port;
 215         struct stm32_port *stm32_port = to_stm32_port(port);
 216         const struct stm32_usart_offsets *ofs = &stm32_port->info->ofs;
 217         unsigned long c;
 218         u32 sr;
 219         char flag;
 220
 221         spin_lock(&port->lock);
 222
 223         while (stm32_usart_pending_rx(port, &sr, &stm32_port->last_res,
 224                                       threaded)) {
 225                 sr |= USART_SR_DUMMY_RX;
 226                 flag = TTY_NORMAL;
 227
 228                 /*
 229                  * Status bits has to be cleared before reading the RDR:
 230                  * In FIFO mode, reading the RDR will pop the next data
 231                  * (if any) along with its status bits into the SR.
 232                  * Not doing so leads to misalignement between RDR and SR,
 233                  * and clear status bits of the next rx data.
 234                  *
 235                  * Clear errors flags for stm32f7 and stm32h7 compatible
 236                  * devices. On stm32f4 compatible devices, the error bit is
 237                  * cleared by the sequence [read SR - read DR].
 238                  */
 239                 if ((sr & USART_SR_ERR_MASK) && ofs->icr != UNDEF_REG)
 240                         writel_relaxed(sr & USART_SR_ERR_MASK,
 241                                        port->membase + ofs->icr);
 242
 243                 c = stm32_usart_get_char(port, &sr, &stm32_port->last_res);
 244                 port->icount.rx++;
 245                 if (sr & USART_SR_ERR_MASK) {
 246                         if (sr & USART_SR_ORE) {
 247                                 port->icount.overrun++;
 248                         } else if (sr & USART_SR_PE) {
 249                                 port->icount.parity++;
 250                         } else if (sr & USART_SR_FE) {
 251                                 /* Break detection if character is null */
 252                                 if (!c) {
 253                                         port->icount.brk++;
 254                                         if (uart_handle_break(port))
 255                                                 continue;
 256                                 } else {
 257                                         port->icount.frame++;
 258                                 }
 259                         }
 260
 261                         sr &= port->read_status_mask;
 262
 263                         if (sr & USART_SR_PE) {
 264                                 flag = TTY_PARITY;
 265                         } else if (sr & USART_SR_FE) {
 266                                 if (!c)
 267                                         flag = TTY_BREAK;
 268                                 else
 269                                         flag = TTY_FRAME;
 270                         }
 271                 }
 272
 273                 if (uart_prepare_sysrq_char(port, c))
 274                         continue;
 275                 uart_insert_char(port, sr, USART_SR_ORE, c, flag);
 276         }
 277
 278         uart_unlock_and_check_sysrq(port);
 279
 280         tty_flip_buffer_push(tport);
 281 }
 282
 283 static void stm32_usart_tx_dma_complete(void *arg)
 284 {
 285         struct uart_port *port = arg;
 286         struct stm32_port *stm32port = to_stm32_port(port);
 287         const struct stm32_usart_offsets *ofs = &stm32port->info->ofs;
 288         unsigned long flags;
 289
 290         dmaengine_terminate_async(stm32port->tx_ch);
 291         stm32_usart_clr_bits(port, ofs->cr3, USART_CR3_DMAT);
 292         stm32port->tx_dma_busy = false;
 293
 294         /* Let's see if we have pending data to send */
 295         spin_lock_irqsave(&port->lock, flags);
 296         stm32_usart_transmit_chars(port);
 297         spin_unlock_irqrestore(&port->lock, flags);
 298 }
 299
 300 static void stm32_usart_tx_interrupt_enable(struct uart_port *port)
 301 {
 302         struct stm32_port *stm32_port = to_stm32_port(port);
 303         const struct stm32_usart_offsets *ofs = &stm32_port->info->ofs;
 304
 305         /*
 306          * Enables TX FIFO threashold irq when FIFO is enabled,
 307          * or TX empty irq when FIFO is disabled
 308          */
 309         if (stm32_port->fifoen && stm32_port->txftcfg >= 0)
 310                 stm32_usart_set_bits(port, ofs->cr3, USART_CR3_TXFTIE);
 311         else
 312                 stm32_usart_set_bits(port, ofs->cr1, USART_CR1_TXEIE);
 313 }
 314
 315 static void stm32_usart_tx_interrupt_disable(struct uart_port *port)
 316 {
 317         struct stm32_port *stm32_port = to_stm32_port(port);
 318         const struct stm32_usart_offsets *ofs = &stm32_port->info->ofs;
 319
 320         if (stm32_port->fifoen && stm32_port->txftcfg >= 0)
 321                 stm32_usart_clr_bits(port, ofs->cr3, USART_CR3_TXFTIE);
 322         else
 323                 stm32_usart_clr_bits(port, ofs->cr1, USART_CR1_TXEIE);
 324 }
 325
 326 static void stm32_usart_transmit_chars_pio(struct uart_port *port)
 327 {
 328         struct stm32_port *stm32_port = to_stm32_port(port);
 329         const struct stm32_usart_offsets *ofs = &stm32_port->info->ofs;
 330         struct circ_buf *xmit = &port->state->xmit;
 331
 332         if (stm32_port->tx_dma_busy) {
 333                 stm32_usart_clr_bits(port, ofs->cr3, USART_CR3_DMAT);
 334                 stm32_port->tx_dma_busy = false;
 335         }
 336
 337         while (!uart_circ_empty(xmit)) {
 338                 /* Check that TDR is empty before filling FIFO */
 339                 if (!(readl_relaxed(port->membase + ofs->isr) & USART_SR_TXE))
 340                         break;
 341                 writel_relaxed(xmit->buf[xmit->tail], port->membase + ofs->tdr);
 342                 xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);
 343                 port->icount.tx++;
 344         }
 345
 346         /* rely on TXE irq (mask or unmask) for sending remaining data */
 347         if (uart_circ_empty(xmit))
 348                 stm32_usart_tx_interrupt_disable(port);
 349         else
 350                 stm32_usart_tx_interrupt_enable(port);
 351 }
 352
 353 static void stm32_usart_transmit_chars_dma(struct uart_port *port)
 354 {
 355         struct stm32_port *stm32port = to_stm32_port(port);
 356         const struct stm32_usart_offsets *ofs = &stm32port->info->ofs;
 357         struct circ_buf *xmit = &port->state->xmit;
 358         struct dma_async_tx_descriptor *desc = NULL;
 359         unsigned int count, i;
 360
 361         if (stm32port->tx_dma_busy)
 362                 return;
 363
 364         stm32port->tx_dma_busy = true;
 365
 366         count = uart_circ_chars_pending(xmit);
 367
 368         if (count > TX_BUF_L)
 369                 count = TX_BUF_L;
 370
 371         if (xmit->tail < xmit->head) {
 372                 memcpy(&stm32port->tx_buf[0], &xmit->buf[xmit->tail], count);
 373         } else {
 374                 size_t one = UART_XMIT_SIZE - xmit->tail;
 375                 size_t two;
 376
 377                 if (one > count)
 378                         one = count;
 379                 two = count - one;
 380
 381                 memcpy(&stm32port->tx_buf[0], &xmit->buf[xmit->tail], one);
 382                 if (two)
 383                         memcpy(&stm32port->tx_buf[one], &xmit->buf[0], two);
 384         }
 385
 386         desc = dmaengine_prep_slave_single(stm32port->tx_ch,
 387                                            stm32port->tx_dma_buf,
 388                                            count,
 389                                            DMA_MEM_TO_DEV,
 390                                            DMA_PREP_INTERRUPT);
 391
 392         if (!desc)
 393                 goto fallback_err;
 394
 395         desc->callback = stm32_usart_tx_dma_complete;
 396         desc->callback_param = port;
 397
 398         /* Push current DMA TX transaction in the pending queue */
 399         if (dma_submit_error(dmaengine_submit(desc))) {
 400                 /* dma no yet started, safe to free resources */
 401                 dmaengine_terminate_async(stm32port->tx_ch);
 402                 goto fallback_err;
 403         }
 404
 405         /* Issue pending DMA TX requests */
 406         dma_async_issue_pending(stm32port->tx_ch);
 407
 408         stm32_usart_set_bits(port, ofs->cr3, USART_CR3_DMAT);
 409
 410         xmit->tail = (xmit->tail + count) & (UART_XMIT_SIZE - 1);
 411         port->icount.tx += count;
 412         return;
 413
 414 fallback_err:
 415         for (i = count; i > 0; i--)
 416                 stm32_usart_transmit_chars_pio(port);
 417 }
 418
 419 static void stm32_usart_transmit_chars(struct uart_port *port)
 420 {
 421         struct stm32_port *stm32_port = to_stm32_port(port);
 422         const struct stm32_usart_offsets *ofs = &stm32_port->info->ofs;
 423         struct circ_buf *xmit = &port->state->xmit;
 424
 425         if (port->x_char) {
 426                 if (stm32_port->tx_dma_busy)
 427                         stm32_usart_clr_bits(port, ofs->cr3, USART_CR3_DMAT);
 428                 writel_relaxed(port->x_char, port->membase + ofs->tdr);
 429                 port->x_char = 0;
 430                 port->icount.tx++;
 431                 if (stm32_port->tx_dma_busy)
 432                         stm32_usart_set_bits(port, ofs->cr3, USART_CR3_DMAT);
 433                 return;
 434         }
 435
 436         if (uart_circ_empty(xmit) || uart_tx_stopped(port)) {
 437                 stm32_usart_tx_interrupt_disable(port);
 438                 return;
 439         }
 440
 441         if (ofs->icr == UNDEF_REG)
 442                 stm32_usart_clr_bits(port, ofs->isr, USART_SR_TC);
 443         else
 444                 writel_relaxed(USART_ICR_TCCF, port->membase + ofs->icr);
 445
 446         if (stm32_port->tx_ch)
 447                 stm32_usart_transmit_chars_dma(port);
 448         else
 449                 stm32_usart_transmit_chars_pio(port);
 450
 451         if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
 452                 uart_write_wakeup(port);
 453
 454         if (uart_circ_empty(xmit))
 455                 stm32_usart_tx_interrupt_disable(port);
 456 }
 457
 458 static irqreturn_t stm32_usart_interrupt(int irq, void *ptr)
 459 {
 460         struct uart_port *port = ptr;
 461         struct tty_port *tport = &port->state->port;
 462         struct stm32_port *stm32_port = to_stm32_port(port);
 463         const struct stm32_usart_offsets *ofs = &stm32_port->info->ofs;
 464         u32 sr;
 465
 466         sr = readl_relaxed(port->membase + ofs->isr);
 467
 468         if ((sr & USART_SR_RTOF) && ofs->icr != UNDEF_REG)
 469                 writel_relaxed(USART_ICR_RTOCF,
 470                                port->membase + ofs->icr);
 471
 472         if ((sr & USART_SR_WUF) && ofs->icr != UNDEF_REG) {
 473                 /* Clear wake up flag and disable wake up interrupt */
 474                 writel_relaxed(USART_ICR_WUCF,
 475                                port->membase + ofs->icr);
 476                 stm32_usart_clr_bits(port, ofs->cr3, USART_CR3_WUFIE);
 477                 if (irqd_is_wakeup_set(irq_get_irq_data(port->irq)))
 478                         pm_wakeup_event(tport->tty->dev, 0);
 479         }
 480
 481         if ((sr & USART_SR_RXNE) && !(stm32_port->rx_ch))
 482                 stm32_usart_receive_chars(port, false);
 483
 484         if ((sr & USART_SR_TXE) && !(stm32_port->tx_ch)) {
 485                 spin_lock(&port->lock);
 486                 stm32_usart_transmit_chars(port);
 487                 spin_unlock(&port->lock);
 488         }
 489
 490         if (stm32_port->rx_ch)
 491                 return IRQ_WAKE_THREAD;
 492         else
 493                 return IRQ_HANDLED;
 494 }
 495
 496 static irqreturn_t stm32_usart_threaded_interrupt(int irq, void *ptr)
 497 {
 498         struct uart_port *port = ptr;
 499         struct stm32_port *stm32_port = to_stm32_port(port);
 500
 501         if (stm32_port->rx_ch)
 502                 stm32_usart_receive_chars(port, true);
 503
 504         return IRQ_HANDLED;
 505 }
 506
 507 static unsigned int stm32_usart_tx_empty(struct uart_port *port)
 508 {
 509         struct stm32_port *stm32_port = to_stm32_port(port);
 510         const struct stm32_usart_offsets *ofs = &stm32_port->info->ofs;
 511
 512         if (readl_relaxed(port->membase + ofs->isr) & USART_SR_TC)
 513                 return TIOCSER_TEMT;
 514
 515         return 0;
 516 }
 517
 518 static void stm32_usart_set_mctrl(struct uart_port *port, unsigned int mctrl)
 519 {
 520         struct stm32_port *stm32_port = to_stm32_port(port);
 521         const struct stm32_usart_offsets *ofs = &stm32_port->info->ofs;
 522
 523         if ((mctrl & TIOCM_RTS) && (port->status & UPSTAT_AUTORTS))
 524                 stm32_usart_set_bits(port, ofs->cr3, USART_CR3_RTSE);
 525         else
 526                 stm32_usart_clr_bits(port, ofs->cr3, USART_CR3_RTSE);
 527
 528         mctrl_gpio_set(stm32_port->gpios, mctrl);
 529 }
 530
 531 static unsigned int stm32_usart_get_mctrl(struct uart_port *port)
 532 {
 533         struct stm32_port *stm32_port = to_stm32_port(port);
 534         unsigned int ret;
 535
 536         /* This routine is used to get signals of: DCD, DSR, RI, and CTS */
 537         ret = TIOCM_CAR | TIOCM_DSR | TIOCM_CTS;
 538
 539         return mctrl_gpio_get(stm32_port->gpios, &ret);
 540 }
 541
 542 static void stm32_usart_enable_ms(struct uart_port *port)
 543 {
 544         mctrl_gpio_enable_ms(to_stm32_port(port)->gpios);
 545 }
 546
 547 static void stm32_usart_disable_ms(struct uart_port *port)
 548 {
 549         mctrl_gpio_disable_ms(to_stm32_port(port)->gpios);
 550 }
 551
 552 /* Transmit stop */
 553 static void stm32_usart_stop_tx(struct uart_port *port)
 554 {
 555         struct stm32_port *stm32_port = to_stm32_port(port);
 556         struct serial_rs485 *rs485conf = &port->rs485;
 557
 558         stm32_usart_tx_interrupt_disable(port);
 559
 560         if (rs485conf->flags & SER_RS485_ENABLED) {
 561                 if (rs485conf->flags & SER_RS485_RTS_ON_SEND) {
 562                         mctrl_gpio_set(stm32_port->gpios,
 563                                         stm32_port->port.mctrl & ~TIOCM_RTS);
 564                 } else {
 565                         mctrl_gpio_set(stm32_port->gpios,
 566                                         stm32_port->port.mctrl | TIOCM_RTS);
 567                 }
 568         }
 569 }
 570
 571 /* There are probably characters waiting to be transmitted. */
 572 static void stm32_usart_start_tx(struct uart_port *port)
 573 {
 574         struct stm32_port *stm32_port = to_stm32_port(port);
 575         struct serial_rs485 *rs485conf = &port->rs485;
 576         struct circ_buf *xmit = &port->state->xmit;
 577
 578         if (uart_circ_empty(xmit))
 579                 return;
 580
 581         if (rs485conf->flags & SER_RS485_ENABLED) {
 582                 if (rs485conf->flags & SER_RS485_RTS_ON_SEND) {
 583                         mctrl_gpio_set(stm32_port->gpios,
 584                                         stm32_port->port.mctrl | TIOCM_RTS);
 585                 } else {
 586                         mctrl_gpio_set(stm32_port->gpios,
 587                                         stm32_port->port.mctrl & ~TIOCM_RTS);
 588                 }
 589         }
 590
 591         stm32_usart_transmit_chars(port);
 592 }
 593
 594 /* Flush the transmit buffer. */
 595 static void stm32_usart_flush_buffer(struct uart_port *port)
 596 {
 597         struct stm32_port *stm32_port = to_stm32_port(port);
 598         const struct stm32_usart_offsets *ofs = &stm32_port->info->ofs;
 599
 600         if (stm32_port->tx_ch) {
 601                 dmaengine_terminate_async(stm32_port->tx_ch);
 602                 stm32_usart_clr_bits(port, ofs->cr3, USART_CR3_DMAT);
 603                 stm32_port->tx_dma_busy = false;
 604         }
 605 }
 606
 607 /* Throttle the remote when input buffer is about to overflow. */
 608 static void stm32_usart_throttle(struct uart_port *port)
 609 {
 610         struct stm32_port *stm32_port = to_stm32_port(port);
 611         const struct stm32_usart_offsets *ofs = &stm32_port->info->ofs;
 612         unsigned long flags;
 613
 614         spin_lock_irqsave(&port->lock, flags);
 615         stm32_usart_clr_bits(port, ofs->cr1, stm32_port->cr1_irq);
 616         if (stm32_port->cr3_irq)
 617                 stm32_usart_clr_bits(port, ofs->cr3, stm32_port->cr3_irq);
 618
 619         spin_unlock_irqrestore(&port->lock, flags);
 620 }
 621
 622 /* Unthrottle the remote, the input buffer can now accept data. */
 623 static void stm32_usart_unthrottle(struct uart_port *port)
 624 {
 625         struct stm32_port *stm32_port = to_stm32_port(port);
 626         const struct stm32_usart_offsets *ofs = &stm32_port->info->ofs;
 627         unsigned long flags;
 628
 629         spin_lock_irqsave(&port->lock, flags);
 630         stm32_usart_set_bits(port, ofs->cr1, stm32_port->cr1_irq);
 631         if (stm32_port->cr3_irq)
 632                 stm32_usart_set_bits(port, ofs->cr3, stm32_port->cr3_irq);
 633
 634         spin_unlock_irqrestore(&port->lock, flags);
 635 }
 636
 637 /* Receive stop */
 638 static void stm32_usart_stop_rx(struct uart_port *port)
 639 {
 640         struct stm32_port *stm32_port = to_stm32_port(port);
 641         const struct stm32_usart_offsets *ofs = &stm32_port->info->ofs;
 642
 643         stm32_usart_clr_bits(port, ofs->cr1, stm32_port->cr1_irq);
 644         if (stm32_port->cr3_irq)
 645                 stm32_usart_clr_bits(port, ofs->cr3, stm32_port->cr3_irq);
 646 }
 647
 648 /* Handle breaks - ignored by us */
 649 static void stm32_usart_break_ctl(struct uart_port *port, int break_state)
 650 {
 651 }
 652
 653 static int stm32_usart_startup(struct uart_port *port)
 654 {
 655         struct stm32_port *stm32_port = to_stm32_port(port);
 656         const struct stm32_usart_offsets *ofs = &stm32_port->info->ofs;
 657         const struct stm32_usart_config *cfg = &stm32_port->info->cfg;
 658         const char *name = to_platform_device(port->dev)->name;
 659         u32 val;
 660         int ret;
 661
 662         ret = request_threaded_irq(port->irq, stm32_usart_interrupt,
 663                                    stm32_usart_threaded_interrupt,
 664                                    IRQF_ONESHOT | IRQF_NO_SUSPEND,
 665                                    name, port);
 666         if (ret)
 667                 return ret;
 668
 669         if (stm32_port->swap) {
 670                 val = readl_relaxed(port->membase + ofs->cr2);
 671                 val |= USART_CR2_SWAP;
 672                 writel_relaxed(val, port->membase + ofs->cr2);
 673         }
 674
 675         /* RX FIFO Flush */
 676         if (ofs->rqr != UNDEF_REG)
 677                 writel_relaxed(USART_RQR_RXFRQ, port->membase + ofs->rqr);
 678
 679         /* RX enabling */
 680         val = stm32_port->cr1_irq | USART_CR1_RE | BIT(cfg->uart_enable_bit);
 681         stm32_usart_set_bits(port, ofs->cr1, val);
 682
 683         return 0;
 684 }
 685
 686 static void stm32_usart_shutdown(struct uart_port *port)
 687 {
 688         struct stm32_port *stm32_port = to_stm32_port(port);
 689         const struct stm32_usart_offsets *ofs = &stm32_port->info->ofs;
 690         const struct stm32_usart_config *cfg = &stm32_port->info->cfg;
 691         u32 val, isr;
 692         int ret;
 693
 694         /* Disable modem control interrupts */
 695         stm32_usart_disable_ms(port);
 696
 697         val = USART_CR1_TXEIE | USART_CR1_TE;
 698         val |= stm32_port->cr1_irq | USART_CR1_RE;
 699         val |= BIT(cfg->uart_enable_bit);
 700         if (stm32_port->fifoen)
 701                 val |= USART_CR1_FIFOEN;
 702
 703         ret = readl_relaxed_poll_timeout(port->membase + ofs->isr,
 704                                          isr, (isr & USART_SR_TC),
 705                                          10, 100000);
 706
 707         /* Send the TC error message only when ISR_TC is not set */
 708         if (ret)
 709                 dev_err(port->dev, "Transmission is not complete\n");
 710
 711         /* flush RX & TX FIFO */
 712         if (ofs->rqr != UNDEF_REG)
 713                 writel_relaxed(USART_RQR_TXFRQ | USART_RQR_RXFRQ,
 714                                port->membase + ofs->rqr);
 715
 716         stm32_usart_clr_bits(port, ofs->cr1, val);
 717
 718         free_irq(port->irq, port);
 719 }
 720
 721 static void stm32_usart_set_termios(struct uart_port *port,
 722                                     struct ktermios *termios,
 723                                     struct ktermios *old)
 724 {
 725         struct stm32_port *stm32_port = to_stm32_port(port);
 726         const struct stm32_usart_offsets *ofs = &stm32_port->info->ofs;
 727         const struct stm32_usart_config *cfg = &stm32_port->info->cfg;
 728         struct serial_rs485 *rs485conf = &port->rs485;
 729         unsigned int baud, bits;
 730         u32 usartdiv, mantissa, fraction, oversampling;
 731         tcflag_t cflag = termios->c_cflag;
 732         u32 cr1, cr2, cr3, isr;
 733         unsigned long flags;
 734         int ret;
 735
 736         if (!stm32_port->hw_flow_control)
 737                 cflag &= ~CRTSCTS;
 738
 739         baud = uart_get_baud_rate(port, termios, old, 0, port->uartclk / 8);
 740
 741         spin_lock_irqsave(&port->lock, flags);
 742
 743         ret = readl_relaxed_poll_timeout_atomic(port->membase + ofs->isr,
 744                                                 isr,
 745                                                 (isr & USART_SR_TC),
 746                                                 10, 100000);
 747
 748         /* Send the TC error message only when ISR_TC is not set. */
 749         if (ret)
 750                 dev_err(port->dev, "Transmission is not complete\n");
 751
 752         /* Stop serial port and reset value */
 753         writel_relaxed(0, port->membase + ofs->cr1);
 754
 755         /* flush RX & TX FIFO */
 756         if (ofs->rqr != UNDEF_REG)
 757                 writel_relaxed(USART_RQR_TXFRQ | USART_RQR_RXFRQ,
 758                                port->membase + ofs->rqr);
 759
 760         cr1 = USART_CR1_TE | USART_CR1_RE;
 761         if (stm32_port->fifoen)
 762                 cr1 |= USART_CR1_FIFOEN;
 763         cr2 = stm32_port->swap ? USART_CR2_SWAP : 0;
 764
 765         /* Tx and RX FIFO configuration */
 766         cr3 = readl_relaxed(port->membase + ofs->cr3);
 767         cr3 &= USART_CR3_TXFTIE | USART_CR3_RXFTIE;
 768         if (stm32_port->fifoen) {
 769                 if (stm32_port->txftcfg >= 0)
 770                         cr3 |= stm32_port->txftcfg << USART_CR3_TXFTCFG_SHIFT;
 771                 if (stm32_port->rxftcfg >= 0)
 772                         cr3 |= stm32_port->rxftcfg << USART_CR3_RXFTCFG_SHIFT;
 773         }
 774
 775         if (cflag & CSTOPB)
 776                 cr2 |= USART_CR2_STOP_2B;
 777
 778         bits = tty_get_char_size(cflag);
 779         stm32_port->rdr_mask = (BIT(bits) - 1);
 780
 781         if (cflag & PARENB) {
 782                 bits++;
 783                 cr1 |= USART_CR1_PCE;
 784         }
 785
 786         /*
 787          * Word length configuration:
 788          * CS8 + parity, 9 bits word aka [M1:M0] = 0b01
 789          * CS7 or (CS6 + parity), 7 bits word aka [M1:M0] = 0b10
 790          * CS8 or (CS7 + parity), 8 bits word aka [M1:M0] = 0b00
 791          * M0 and M1 already cleared by cr1 initialization.
 792          */
 793         if (bits == 9)
 794                 cr1 |= USART_CR1_M0;
 795         else if ((bits == 7) && cfg->has_7bits_data)
 796                 cr1 |= USART_CR1_M1;
 797         else if (bits != 8)
 798                 dev_dbg(port->dev, "Unsupported data bits config: %u bits\n"
 799                         , bits);
 800
 801         if (ofs->rtor != UNDEF_REG && (stm32_port->rx_ch ||
 802                                        (stm32_port->fifoen &&
 803                                         stm32_port->rxftcfg >= 0))) {
 804                 if (cflag & CSTOPB)
 805                         bits = bits + 3; /* 1 start bit + 2 stop bits */
 806                 else
 807                         bits = bits + 2; /* 1 start bit + 1 stop bit */
 808
 809                 /* RX timeout irq to occur after last stop bit + bits */
 810                 stm32_port->cr1_irq = USART_CR1_RTOIE;
 811                 writel_relaxed(bits, port->membase + ofs->rtor);
 812                 cr2 |= USART_CR2_RTOEN;
 813                 /* Not using dma, enable fifo threshold irq */
 814                 if (!stm32_port->rx_ch)
 815                         stm32_port->cr3_irq =  USART_CR3_RXFTIE;
 816         }
 817
 818         cr1 |= stm32_port->cr1_irq;
 819         cr3 |= stm32_port->cr3_irq;
 820
 821         if (cflag & PARODD)
 822                 cr1 |= USART_CR1_PS;
 823
 824         port->status &= ~(UPSTAT_AUTOCTS | UPSTAT_AUTORTS);
 825         if (cflag & CRTSCTS) {
 826                 port->status |= UPSTAT_AUTOCTS | UPSTAT_AUTORTS;
 827                 cr3 |= USART_CR3_CTSE | USART_CR3_RTSE;
 828         }
 829
 830         usartdiv = DIV_ROUND_CLOSEST(port->uartclk, baud);
 831
 832         /*
 833          * The USART supports 16 or 8 times oversampling.
 834          * By default we prefer 16 times oversampling, so that the receiver
 835          * has a better tolerance to clock deviations.
 836          * 8 times oversampling is only used to achieve higher speeds.
 837          */
 838         if (usartdiv < 16) {
 839                 oversampling = 8;
 840                 cr1 |= USART_CR1_OVER8;
 841                 stm32_usart_set_bits(port, ofs->cr1, USART_CR1_OVER8);
 842         } else {
 843                 oversampling = 16;
 844                 cr1 &= ~USART_CR1_OVER8;
 845                 stm32_usart_clr_bits(port, ofs->cr1, USART_CR1_OVER8);
 846         }
 847
 848         mantissa = (usartdiv / oversampling) << USART_BRR_DIV_M_SHIFT;
 849         fraction = usartdiv % oversampling;
 850         writel_relaxed(mantissa | fraction, port->membase + ofs->brr);
 851
 852         uart_update_timeout(port, cflag, baud);
 853
 854         port->read_status_mask = USART_SR_ORE;
 855         if (termios->c_iflag & INPCK)
 856                 port->read_status_mask |= USART_SR_PE | USART_SR_FE;
 857         if (termios->c_iflag & (IGNBRK | BRKINT | PARMRK))
 858                 port->read_status_mask |= USART_SR_FE;
 859
 860         /* Characters to ignore */
 861         port->ignore_status_mask = 0;
 862         if (termios->c_iflag & IGNPAR)
 863                 port->ignore_status_mask = USART_SR_PE | USART_SR_FE;
 864         if (termios->c_iflag & IGNBRK) {
 865                 port->ignore_status_mask |= USART_SR_FE;
 866                 /*
 867                  * If we're ignoring parity and break indicators,
 868                  * ignore overruns too (for real raw support).
 869                  */
 870                 if (termios->c_iflag & IGNPAR)
 871                         port->ignore_status_mask |= USART_SR_ORE;
 872         }
 873
 874         /* Ignore all characters if CREAD is not set */
 875         if ((termios->c_cflag & CREAD) == 0)
 876                 port->ignore_status_mask |= USART_SR_DUMMY_RX;
 877
 878         if (stm32_port->rx_ch)
 879                 cr3 |= USART_CR3_DMAR;
 880
 881         if (rs485conf->flags & SER_RS485_ENABLED) {
 882                 stm32_usart_config_reg_rs485(&cr1, &cr3,
 883                                              rs485conf->delay_rts_before_send,
 884                                              rs485conf->delay_rts_after_send,
 885                                              baud);
 886                 if (rs485conf->flags & SER_RS485_RTS_ON_SEND) {
 887                         cr3 &= ~USART_CR3_DEP;
 888                         rs485conf->flags &= ~SER_RS485_RTS_AFTER_SEND;
 889                 } else {
 890                         cr3 |= USART_CR3_DEP;
 891                         rs485conf->flags |= SER_RS485_RTS_AFTER_SEND;
 892                 }
 893
 894         } else {
 895                 cr3 &= ~(USART_CR3_DEM | USART_CR3_DEP);
 896                 cr1 &= ~(USART_CR1_DEDT_MASK | USART_CR1_DEAT_MASK);
 897         }
 898
 899         /* Configure wake up from low power on start bit detection */
 900         if (stm32_port->wakeup_src) {
 901                 cr3 &= ~USART_CR3_WUS_MASK;
 902                 cr3 |= USART_CR3_WUS_START_BIT;
 903         }
 904
 905         writel_relaxed(cr3, port->membase + ofs->cr3);
 906         writel_relaxed(cr2, port->membase + ofs->cr2);
 907         writel_relaxed(cr1, port->membase + ofs->cr1);
 908
 909         stm32_usart_set_bits(port, ofs->cr1, BIT(cfg->uart_enable_bit));
 910         spin_unlock_irqrestore(&port->lock, flags);
 911
 912         /* Handle modem control interrupts */
 913         if (UART_ENABLE_MS(port, termios->c_cflag))
 914                 stm32_usart_enable_ms(port);
 915         else
 916                 stm32_usart_disable_ms(port);
 917 }
 918
 919 static const char *stm32_usart_type(struct uart_port *port)
 920 {
 921         return (port->type == PORT_STM32) ? DRIVER_NAME : NULL;
 922 }
 923
 924 static void stm32_usart_release_port(struct uart_port *port)
 925 {
 926 }
 927
 928 static int stm32_usart_request_port(struct uart_port *port)
 929 {
 930         return 0;
 931 }
 932
 933 static void stm32_usart_config_port(struct uart_port *port, int flags)
 934 {
 935         if (flags & UART_CONFIG_TYPE)
 936                 port->type = PORT_STM32;
 937 }
 938
 939 static int
 940 stm32_usart_verify_port(struct uart_port *port, struct serial_struct *ser)
 941 {
 942         /* No user changeable parameters */
 943         return -EINVAL;
 944 }
 945
 946 static void stm32_usart_pm(struct uart_port *port, unsigned int state,
 947                            unsigned int oldstate)
 948 {
 949         struct stm32_port *stm32port = container_of(port,
 950                         struct stm32_port, port);
 951         const struct stm32_usart_offsets *ofs = &stm32port->info->ofs;
 952         const struct stm32_usart_config *cfg = &stm32port->info->cfg;
 953         unsigned long flags;
 954
 955         switch (state) {
 956         case UART_PM_STATE_ON:
 957                 pm_runtime_get_sync(port->dev);
 958                 break;
 959         case UART_PM_STATE_OFF:
 960                 spin_lock_irqsave(&port->lock, flags);
 961                 stm32_usart_clr_bits(port, ofs->cr1, BIT(cfg->uart_enable_bit));
 962                 spin_unlock_irqrestore(&port->lock, flags);
 963                 pm_runtime_put_sync(port->dev);
 964                 break;
 965         }
 966 }
 967
 968 static const struct uart_ops stm32_uart_ops = {
 969         .tx_empty       = stm32_usart_tx_empty,
 970         .set_mctrl      = stm32_usart_set_mctrl,
 971         .get_mctrl      = stm32_usart_get_mctrl,
 972         .stop_tx        = stm32_usart_stop_tx,
 973         .start_tx       = stm32_usart_start_tx,
 974         .throttle       = stm32_usart_throttle,
 975         .unthrottle     = stm32_usart_unthrottle,
 976         .stop_rx        = stm32_usart_stop_rx,
 977         .enable_ms      = stm32_usart_enable_ms,
 978         .break_ctl      = stm32_usart_break_ctl,
 979         .startup        = stm32_usart_startup,
 980         .shutdown       = stm32_usart_shutdown,
 981         .flush_buffer   = stm32_usart_flush_buffer,
 982         .set_termios    = stm32_usart_set_termios,
 983         .pm             = stm32_usart_pm,
 984         .type           = stm32_usart_type,
 985         .release_port   = stm32_usart_release_port,
 986         .request_port   = stm32_usart_request_port,
 987         .config_port    = stm32_usart_config_port,
 988         .verify_port    = stm32_usart_verify_port,
 989 };
 990
 991 /*
 992  * STM32H7 RX & TX FIFO threshold configuration (CR3 RXFTCFG / TXFTCFG)
 993  * Note: 1 isn't a valid value in RXFTCFG / TXFTCFG. In this case,
 994  * RXNEIE / TXEIE can be used instead of threshold irqs: RXFTIE / TXFTIE.
 995  * So, RXFTCFG / TXFTCFG bitfields values are encoded as array index + 1.
 996  */
 997 static const u32 stm32h7_usart_fifo_thresh_cfg[] = { 1, 2, 4, 8, 12, 14, 16 };
 998
 999 static void stm32_usart_get_ftcfg(struct platform_device *pdev, const char *p,
1000                                   int *ftcfg)
1001 {
1002         u32 bytes, i;
1003
1004         /* DT option to get RX & TX FIFO threshold (default to 8 bytes) */
1005         if (of_property_read_u32(pdev->dev.of_node, p, &bytes))
1006                 bytes = 8;
1007
1008         for (i = 0; i < ARRAY_SIZE(stm32h7_usart_fifo_thresh_cfg); i++)
1009                 if (stm32h7_usart_fifo_thresh_cfg[i] >= bytes)
1010                         break;
1011         if (i >= ARRAY_SIZE(stm32h7_usart_fifo_thresh_cfg))
1012                 i = ARRAY_SIZE(stm32h7_usart_fifo_thresh_cfg) - 1;
1013
1014         dev_dbg(&pdev->dev, "%s set to %d bytes\n", p,
1015                 stm32h7_usart_fifo_thresh_cfg[i]);
1016
1017         /* Provide FIFO threshold ftcfg (1 is invalid: threshold irq unused) */
1018         if (i)
1019                 *ftcfg = i - 1;
1020         else
1021                 *ftcfg = -EINVAL;
1022 }
1023
1024 static void stm32_usart_deinit_port(struct stm32_port *stm32port)
1025 {
1026         clk_disable_unprepare(stm32port->clk);
1027 }
1028
1029 static int stm32_usart_init_port(struct stm32_port *stm32port,
1030                                  struct platform_device *pdev)
1031 {
1032         struct uart_port *port = &stm32port->port;
1033         struct resource *res;
1034         int ret, irq;
1035
1036         irq = platform_get_irq(pdev, 0);
1037         if (irq <= 0)
1038                 return irq ? : -ENODEV;
1039
1040         port->iotype    = UPIO_MEM;
1041         port->flags     = UPF_BOOT_AUTOCONF;
1042         port->ops       = &stm32_uart_ops;
1043         port->dev       = &pdev->dev;
1044         port->fifosize  = stm32port->info->cfg.fifosize;
1045         port->has_sysrq = IS_ENABLED(CONFIG_SERIAL_STM32_CONSOLE);
1046         port->irq = irq;
1047         port->rs485_config = stm32_usart_config_rs485;
1048
1049         ret = stm32_usart_init_rs485(port, pdev);
1050         if (ret)
1051                 return ret;
1052
1053         stm32port->wakeup_src = stm32port->info->cfg.has_wakeup &&
1054                 of_property_read_bool(pdev->dev.of_node, "wakeup-source");
1055
1056         stm32port->swap = stm32port->info->cfg.has_swap &&
1057                 of_property_read_bool(pdev->dev.of_node, "rx-tx-swap");
1058
1059         stm32port->fifoen = stm32port->info->cfg.has_fifo;
1060         if (stm32port->fifoen) {
1061                 stm32_usart_get_ftcfg(pdev, "rx-threshold",
1062                                       &stm32port->rxftcfg);
1063                 stm32_usart_get_ftcfg(pdev, "tx-threshold",
1064                                       &stm32port->txftcfg);
1065         }
1066
1067         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
1068         port->membase = devm_ioremap_resource(&pdev->dev, res);
1069         if (IS_ERR(port->membase))
1070                 return PTR_ERR(port->membase);
1071         port->mapbase = res->start;
1072
1073         spin_lock_init(&port->lock);
1074
1075         stm32port->clk = devm_clk_get(&pdev->dev, NULL);
1076         if (IS_ERR(stm32port->clk))
1077                 return PTR_ERR(stm32port->clk);
1078
1079         /* Ensure that clk rate is correct by enabling the clk */
1080         ret = clk_prepare_enable(stm32port->clk);
1081         if (ret)
1082                 return ret;
1083
1084         stm32port->port.uartclk = clk_get_rate(stm32port->clk);
1085         if (!stm32port->port.uartclk) {
1086                 ret = -EINVAL;
1087                 goto err_clk;
1088         }
1089
1090         stm32port->gpios = mctrl_gpio_init(&stm32port->port, 0);
1091         if (IS_ERR(stm32port->gpios)) {
1092                 ret = PTR_ERR(stm32port->gpios);
1093                 goto err_clk;
1094         }
1095
1096         /*
1097          * Both CTS/RTS gpios and "st,hw-flow-ctrl" (deprecated) or "uart-has-rtscts"
1098          * properties should not be specified.
1099          */
1100         if (stm32port->hw_flow_control) {
1101                 if (mctrl_gpio_to_gpiod(stm32port->gpios, UART_GPIO_CTS) ||
1102                     mctrl_gpio_to_gpiod(stm32port->gpios, UART_GPIO_RTS)) {
1103                         dev_err(&pdev->dev, "Conflicting RTS/CTS config\n");
1104                         ret = -EINVAL;
1105                         goto err_clk;
1106                 }
1107         }
1108
1109         return ret;
1110
1111 err_clk:
1112         clk_disable_unprepare(stm32port->clk);
1113
1114         return ret;
1115 }
1116
1117 static struct stm32_port *stm32_usart_of_get_port(struct platform_device *pdev)
1118 {
1119         struct device_node *np = pdev->dev.of_node;
1120         int id;
1121
1122         if (!np)
1123                 return NULL;
1124
1125         id = of_alias_get_id(np, "serial");
1126         if (id < 0) {
1127                 dev_err(&pdev->dev, "failed to get alias id, errno %d\n", id);
1128                 return NULL;
1129         }
1130
1131         if (WARN_ON(id >= STM32_MAX_PORTS))
1132                 return NULL;
1133
1134         stm32_ports[id].hw_flow_control =
1135                 of_property_read_bool (np, "st,hw-flow-ctrl") /*deprecated*/ ||
1136                 of_property_read_bool (np, "uart-has-rtscts");
1137         stm32_ports[id].port.line = id;
1138         stm32_ports[id].cr1_irq = USART_CR1_RXNEIE;
1139         stm32_ports[id].cr3_irq = 0;
1140         stm32_ports[id].last_res = RX_BUF_L;
1141         return &stm32_ports[id];
1142 }
1143
1144 #ifdef CONFIG_OF
1145 static const struct of_device_id stm32_match[] = {
1146         { .compatible = "st,stm32-uart", .data = &stm32f4_info},
1147         { .compatible = "st,stm32f7-uart", .data = &stm32f7_info},
1148         { .compatible = "st,stm32h7-uart", .data = &stm32h7_info},
1149         {},
1150 };
1151
1152 MODULE_DEVICE_TABLE(of, stm32_match);
1153 #endif
1154
1155 static void stm32_usart_of_dma_rx_remove(struct stm32_port *stm32port,
1156                                          struct platform_device *pdev)
1157 {
1158         if (stm32port->rx_buf)
1159                 dma_free_coherent(&pdev->dev, RX_BUF_L, stm32port->rx_buf,
1160                                   stm32port->rx_dma_buf);
1161 }
1162
1163 static int stm32_usart_of_dma_rx_probe(struct stm32_port *stm32port,
1164                                        struct platform_device *pdev)
1165 {
1166         const struct stm32_usart_offsets *ofs = &stm32port->info->ofs;
1167         struct uart_port *port = &stm32port->port;
1168         struct device *dev = &pdev->dev;
1169         struct dma_slave_config config;
1170         struct dma_async_tx_descriptor *desc = NULL;
1171         int ret;
1172
1173         /*
1174          * Using DMA and threaded handler for the console could lead to
1175          * deadlocks.
1176          */
1177         if (uart_console(port))
1178                 return -ENODEV;
1179
1180         stm32port->rx_buf = dma_alloc_coherent(&pdev->dev, RX_BUF_L,
1181                                                &stm32port->rx_dma_buf,
1182                                                GFP_KERNEL);
1183         if (!stm32port->rx_buf)
1184                 return -ENOMEM;
1185
1186         /* Configure DMA channel */
1187         memset(&config, 0, sizeof(config));
1188         config.src_addr = port->mapbase + ofs->rdr;
1189         config.src_addr_width = DMA_SLAVE_BUSWIDTH_1_BYTE;
1190
1191         ret = dmaengine_slave_config(stm32port->rx_ch, &config);
1192         if (ret < 0) {
1193                 dev_err(dev, "rx dma channel config failed\n");
1194                 stm32_usart_of_dma_rx_remove(stm32port, pdev);
1195                 return ret;
1196         }
1197
1198         /* Prepare a DMA cyclic transaction */
1199         desc = dmaengine_prep_dma_cyclic(stm32port->rx_ch,
1200                                          stm32port->rx_dma_buf,
1201                                          RX_BUF_L, RX_BUF_P, DMA_DEV_TO_MEM,
1202                                          DMA_PREP_INTERRUPT);
1203         if (!desc) {
1204                 dev_err(dev, "rx dma prep cyclic failed\n");
1205                 stm32_usart_of_dma_rx_remove(stm32port, pdev);
1206                 return -ENODEV;
1207         }
1208
1209         /* No callback as dma buffer is drained on usart interrupt */
1210         desc->callback = NULL;
1211         desc->callback_param = NULL;
1212
1213         /* Push current DMA transaction in the pending queue */
1214         ret = dma_submit_error(dmaengine_submit(desc));
1215         if (ret) {
1216                 dmaengine_terminate_sync(stm32port->rx_ch);
1217                 stm32_usart_of_dma_rx_remove(stm32port, pdev);
1218                 return ret;
1219         }
1220
1221         /* Issue pending DMA requests */
1222         dma_async_issue_pending(stm32port->rx_ch);
1223
1224         return 0;
1225 }
1226
1227 static void stm32_usart_of_dma_tx_remove(struct stm32_port *stm32port,
1228                                          struct platform_device *pdev)
1229 {
1230         if (stm32port->tx_buf)
1231                 dma_free_coherent(&pdev->dev, TX_BUF_L, stm32port->tx_buf,
1232                                   stm32port->tx_dma_buf);
1233 }
1234
1235 static int stm32_usart_of_dma_tx_probe(struct stm32_port *stm32port,
1236                                        struct platform_device *pdev)
1237 {
1238         const struct stm32_usart_offsets *ofs = &stm32port->info->ofs;
1239         struct uart_port *port = &stm32port->port;
1240         struct device *dev = &pdev->dev;
1241         struct dma_slave_config config;
1242         int ret;
1243
1244         stm32port->tx_dma_busy = false;
1245
1246         stm32port->tx_buf = dma_alloc_coherent(&pdev->dev, TX_BUF_L,
1247                                                &stm32port->tx_dma_buf,
1248                                                GFP_KERNEL);
1249         if (!stm32port->tx_buf)
1250                 return -ENOMEM;
1251
1252         /* Configure DMA channel */
1253         memset(&config, 0, sizeof(config));
1254         config.dst_addr = port->mapbase + ofs->tdr;
1255         config.dst_addr_width = DMA_SLAVE_BUSWIDTH_1_BYTE;
1256
1257         ret = dmaengine_slave_config(stm32port->tx_ch, &config);
1258         if (ret < 0) {
1259                 dev_err(dev, "tx dma channel config failed\n");
1260                 stm32_usart_of_dma_tx_remove(stm32port, pdev);
1261                 return ret;
1262         }
1263
1264         return 0;
1265 }
1266
1267 static int stm32_usart_serial_probe(struct platform_device *pdev)
1268 {
1269         struct stm32_port *stm32port;
1270         int ret;
1271
1272         stm32port = stm32_usart_of_get_port(pdev);
1273         if (!stm32port)
1274                 return -ENODEV;
1275
1276         stm32port->info = of_device_get_match_data(&pdev->dev);
1277         if (!stm32port->info)
1278                 return -EINVAL;
1279
1280         ret = stm32_usart_init_port(stm32port, pdev);
1281         if (ret)
1282                 return ret;
1283
1284         if (stm32port->wakeup_src) {
1285                 device_set_wakeup_capable(&pdev->dev, true);
1286                 ret = dev_pm_set_wake_irq(&pdev->dev, stm32port->port.irq);
1287                 if (ret)
1288                         goto err_deinit_port;
1289         }
1290
1291         stm32port->rx_ch = dma_request_chan(&pdev->dev, "rx");
1292         if (PTR_ERR(stm32port->rx_ch) == -EPROBE_DEFER) {
1293                 ret = -EPROBE_DEFER;
1294                 goto err_wakeirq;
1295         }
1296         /* Fall back in interrupt mode for any non-deferral error */
1297         if (IS_ERR(stm32port->rx_ch))
1298                 stm32port->rx_ch = NULL;
1299
1300         stm32port->tx_ch = dma_request_chan(&pdev->dev, "tx");
1301         if (PTR_ERR(stm32port->tx_ch) == -EPROBE_DEFER) {
1302                 ret = -EPROBE_DEFER;
1303                 goto err_dma_rx;
1304         }
1305         /* Fall back in interrupt mode for any non-deferral error */
1306         if (IS_ERR(stm32port->tx_ch))
1307                 stm32port->tx_ch = NULL;
1308
1309         if (stm32port->rx_ch && stm32_usart_of_dma_rx_probe(stm32port, pdev)) {
1310                 /* Fall back in interrupt mode */
1311                 dma_release_channel(stm32port->rx_ch);
1312                 stm32port->rx_ch = NULL;
1313         }
1314
1315         if (stm32port->tx_ch && stm32_usart_of_dma_tx_probe(stm32port, pdev)) {
1316                 /* Fall back in interrupt mode */
1317                 dma_release_channel(stm32port->tx_ch);
1318                 stm32port->tx_ch = NULL;
1319         }
1320
1321         if (!stm32port->rx_ch)
1322                 dev_info(&pdev->dev, "interrupt mode for rx (no dma)\n");
1323         if (!stm32port->tx_ch)
1324                 dev_info(&pdev->dev, "interrupt mode for tx (no dma)\n");
1325
1326         platform_set_drvdata(pdev, &stm32port->port);
1327
1328         pm_runtime_get_noresume(&pdev->dev);
1329         pm_runtime_set_active(&pdev->dev);
1330         pm_runtime_enable(&pdev->dev);
1331
1332         ret = uart_add_one_port(&stm32_usart_driver, &stm32port->port);
1333         if (ret)
1334                 goto err_port;
1335
1336         pm_runtime_put_sync(&pdev->dev);
1337
1338         return 0;
1339
1340 err_port:
1341         pm_runtime_disable(&pdev->dev);
1342         pm_runtime_set_suspended(&pdev->dev);
1343         pm_runtime_put_noidle(&pdev->dev);
1344
1345         if (stm32port->tx_ch) {
1346                 stm32_usart_of_dma_tx_remove(stm32port, pdev);
1347                 dma_release_channel(stm32port->tx_ch);
1348         }
1349
1350         if (stm32port->rx_ch)
1351                 stm32_usart_of_dma_rx_remove(stm32port, pdev);
1352
1353 err_dma_rx:
1354         if (stm32port->rx_ch)
1355                 dma_release_channel(stm32port->rx_ch);
1356
1357 err_wakeirq:
1358         if (stm32port->wakeup_src)
1359                 dev_pm_clear_wake_irq(&pdev->dev);
1360
1361 err_deinit_port:
1362         if (stm32port->wakeup_src)
1363                 device_set_wakeup_capable(&pdev->dev, false);
1364
1365         stm32_usart_deinit_port(stm32port);
1366
1367         return ret;
1368 }
1369
1370 static int stm32_usart_serial_remove(struct platform_device *pdev)
1371 {
1372         struct uart_port *port = platform_get_drvdata(pdev);
1373         struct stm32_port *stm32_port = to_stm32_port(port);
1374         const struct stm32_usart_offsets *ofs = &stm32_port->info->ofs;
1375         int err;
1376
1377         pm_runtime_get_sync(&pdev->dev);
1378         err = uart_remove_one_port(&stm32_usart_driver, port);
1379         if (err)
1380                 return(err);
1381
1382         pm_runtime_disable(&pdev->dev);
1383         pm_runtime_set_suspended(&pdev->dev);
1384         pm_runtime_put_noidle(&pdev->dev);
1385
1386         stm32_usart_clr_bits(port, ofs->cr3, USART_CR3_DMAR);
1387
1388         if (stm32_port->tx_ch) {
1389                 dmaengine_terminate_async(stm32_port->tx_ch);
1390                 stm32_usart_of_dma_tx_remove(stm32_port, pdev);
1391                 dma_release_channel(stm32_port->tx_ch);
1392         }
1393
1394         if (stm32_port->rx_ch) {
1395                 dmaengine_terminate_async(stm32_port->rx_ch);
1396                 stm32_usart_of_dma_rx_remove(stm32_port, pdev);
1397                 dma_release_channel(stm32_port->rx_ch);
1398         }
1399
1400         stm32_usart_clr_bits(port, ofs->cr3, USART_CR3_DMAT);
1401
1402         if (stm32_port->wakeup_src) {
1403                 dev_pm_clear_wake_irq(&pdev->dev);
1404                 device_init_wakeup(&pdev->dev, false);
1405         }
1406
1407         stm32_usart_deinit_port(stm32_port);
1408
1409         return 0;
1410 }
1411
1412 #ifdef CONFIG_SERIAL_STM32_CONSOLE
1413 static void stm32_usart_console_putchar(struct uart_port *port, int ch)
1414 {
1415         struct stm32_port *stm32_port = to_stm32_port(port);
1416         const struct stm32_usart_offsets *ofs = &stm32_port->info->ofs;
1417
1418         while (!(readl_relaxed(port->membase + ofs->isr) & USART_SR_TXE))
1419                 cpu_relax();
1420
1421         writel_relaxed(ch, port->membase + ofs->tdr);
1422 }
1423
1424 static void stm32_usart_console_write(struct console *co, const char *s,
1425                                       unsigned int cnt)
1426 {
1427         struct uart_port *port = &stm32_ports[co->index].port;
1428         struct stm32_port *stm32_port = to_stm32_port(port);
1429         const struct stm32_usart_offsets *ofs = &stm32_port->info->ofs;
1430         const struct stm32_usart_config *cfg = &stm32_port->info->cfg;
1431         unsigned long flags;
1432         u32 old_cr1, new_cr1;
1433         int locked = 1;
1434
1435         if (oops_in_progress)
1436                 locked = spin_trylock_irqsave(&port->lock, flags);
1437         else
1438                 spin_lock_irqsave(&port->lock, flags);
1439
1440         /* Save and disable interrupts, enable the transmitter */
1441         old_cr1 = readl_relaxed(port->membase + ofs->cr1);
1442         new_cr1 = old_cr1 & ~USART_CR1_IE_MASK;
1443         new_cr1 |=  USART_CR1_TE | BIT(cfg->uart_enable_bit);
1444         writel_relaxed(new_cr1, port->membase + ofs->cr1);
1445
1446         uart_console_write(port, s, cnt, stm32_usart_console_putchar);
1447
1448         /* Restore interrupt state */
1449         writel_relaxed(old_cr1, port->membase + ofs->cr1);
1450
1451         if (locked)
1452                 spin_unlock_irqrestore(&port->lock, flags);
1453 }
1454
1455 static int stm32_usart_console_setup(struct console *co, char *options)
1456 {
1457         struct stm32_port *stm32port;
1458         int baud = 9600;
1459         int bits = 8;
1460         int parity = 'n';
1461         int flow = 'n';
1462
1463         if (co->index >= STM32_MAX_PORTS)
1464                 return -ENODEV;
1465
1466         stm32port = &stm32_ports[co->index];
1467
1468         /*
1469          * This driver does not support early console initialization
1470          * (use ARM early printk support instead), so we only expect
1471          * this to be called during the uart port registration when the
1472          * driver gets probed and the port should be mapped at that point.
1473          */
1474         if (stm32port->port.mapbase == 0 || !stm32port->port.membase)
1475                 return -ENXIO;
1476
1477         if (options)
1478                 uart_parse_options(options, &baud, &parity, &bits, &flow);
1479
1480         return uart_set_options(&stm32port->port, co, baud, parity, bits, flow);
1481 }
1482
1483 static struct console stm32_console = {
1484         .name           = STM32_SERIAL_NAME,
1485         .device         = uart_console_device,
1486         .write          = stm32_usart_console_write,
1487         .setup          = stm32_usart_console_setup,
1488         .flags          = CON_PRINTBUFFER,
1489         .index          = -1,
1490         .data           = &stm32_usart_driver,
1491 };
1492
1493 #define STM32_SERIAL_CONSOLE (&stm32_console)
1494
1495 #else
1496 #define STM32_SERIAL_CONSOLE NULL
1497 #endif /* CONFIG_SERIAL_STM32_CONSOLE */
1498
1499 static struct uart_driver stm32_usart_driver = {
1500         .driver_name    = DRIVER_NAME,
1501         .dev_name       = STM32_SERIAL_NAME,
1502         .major          = 0,
1503         .minor          = 0,
1504         .nr             = STM32_MAX_PORTS,
1505         .cons           = STM32_SERIAL_CONSOLE,
1506 };
1507
1508 static void __maybe_unused stm32_usart_serial_en_wakeup(struct uart_port *port,
1509                                                         bool enable)
1510 {
1511         struct stm32_port *stm32_port = to_stm32_port(port);
1512         const struct stm32_usart_offsets *ofs = &stm32_port->info->ofs;
1513
1514         if (!stm32_port->wakeup_src)
1515                 return;
1516
1517         /*
1518          * Enable low-power wake-up and wake-up irq if argument is set to
1519          * "enable", disable low-power wake-up and wake-up irq otherwise
1520          */
1521         if (enable) {
1522                 stm32_usart_set_bits(port, ofs->cr1, USART_CR1_UESM);
1523                 stm32_usart_set_bits(port, ofs->cr3, USART_CR3_WUFIE);
1524         } else {
1525                 stm32_usart_clr_bits(port, ofs->cr1, USART_CR1_UESM);
1526                 stm32_usart_clr_bits(port, ofs->cr3, USART_CR3_WUFIE);
1527         }
1528 }
1529
1530 static int __maybe_unused stm32_usart_serial_suspend(struct device *dev)
1531 {
1532         struct uart_port *port = dev_get_drvdata(dev);
1533
1534         uart_suspend_port(&stm32_usart_driver, port);
1535
1536         if (device_may_wakeup(dev) || device_wakeup_path(dev))
1537                 stm32_usart_serial_en_wakeup(port, true);
1538
1539         /*
1540          * When "no_console_suspend" is enabled, keep the pinctrl default state
1541          * and rely on bootloader stage to restore this state upon resume.
1542          * Otherwise, apply the idle or sleep states depending on wakeup
1543          * capabilities.
1544          */
1545         if (console_suspend_enabled || !uart_console(port)) {
1546                 if (device_may_wakeup(dev) || device_wakeup_path(dev))
1547                         pinctrl_pm_select_idle_state(dev);
1548                 else
1549                         pinctrl_pm_select_sleep_state(dev);
1550         }
1551
1552         return 0;
1553 }
1554
1555 static int __maybe_unused stm32_usart_serial_resume(struct device *dev)
1556 {
1557         struct uart_port *port = dev_get_drvdata(dev);
1558
1559         pinctrl_pm_select_default_state(dev);
1560
1561         if (device_may_wakeup(dev) || device_wakeup_path(dev))
1562                 stm32_usart_serial_en_wakeup(port, false);
1563
1564         return uart_resume_port(&stm32_usart_driver, port);
1565 }
1566
1567 static int __maybe_unused stm32_usart_runtime_suspend(struct device *dev)
1568 {
1569         struct uart_port *port = dev_get_drvdata(dev);
1570         struct stm32_port *stm32port = container_of(port,
1571                         struct stm32_port, port);
1572
1573         clk_disable_unprepare(stm32port->clk);
1574
1575         return 0;
1576 }
1577
1578 static int __maybe_unused stm32_usart_runtime_resume(struct device *dev)
1579 {
1580         struct uart_port *port = dev_get_drvdata(dev);
1581         struct stm32_port *stm32port = container_of(port,
1582                         struct stm32_port, port);
1583
1584         return clk_prepare_enable(stm32port->clk);
1585 }
1586
1587 static const struct dev_pm_ops stm32_serial_pm_ops = {
1588         SET_RUNTIME_PM_OPS(stm32_usart_runtime_suspend,
1589                            stm32_usart_runtime_resume, NULL)
1590         SET_SYSTEM_SLEEP_PM_OPS(stm32_usart_serial_suspend,
1591                                 stm32_usart_serial_resume)
1592 };
1593
1594 static struct platform_driver stm32_serial_driver = {
1595         .probe          = stm32_usart_serial_probe,
1596         .remove         = stm32_usart_serial_remove,
1597         .driver = {
1598                 .name   = DRIVER_NAME,
1599                 .pm     = &stm32_serial_pm_ops,
1600                 .of_match_table = of_match_ptr(stm32_match),
1601         },
1602 };
1603
1604 static int __init stm32_usart_init(void)
1605 {
1606         static char banner[] __initdata = "STM32 USART driver initialized";
1607         int ret;
1608
1609         pr_info("%s\n", banner);
1610
1611         ret = uart_register_driver(&stm32_usart_driver);
1612         if (ret)
1613                 return ret;
1614
1615         ret = platform_driver_register(&stm32_serial_driver);
1616         if (ret)
1617                 uart_unregister_driver(&stm32_usart_driver);
1618
1619         return ret;
1620 }
1621
1622 static void __exit stm32_usart_exit(void)
1623 {
1624         platform_driver_unregister(&stm32_serial_driver);
1625         uart_unregister_driver(&stm32_usart_driver);
1626 }
1627
1628 module_init(stm32_usart_init);
1629 module_exit(stm32_usart_exit);
1630
1631 MODULE_ALIAS("platform:" DRIVER_NAME);
1632 MODULE_DESCRIPTION("STMicroelectronics STM32 serial port driver");
1633 MODULE_LICENSE("GPL v2");